During the synthesis, reagents are continuously circulated and real time UV monitoring enables the automatic optimization of reaction parameters like deprotection, coupling times, and wash steps. This leads to a greater coupling yield, superior peptides, and also saves time and reduces reagent waste. UV monitoring uses a long life LED light source. The MultiPep CF can be upgraded with a 72 column module for parallel synthesis of peptides at 10-500 μmol scales. Options for the instrument include vortexing, heating, and inert gas.